I don't really know who to follow on Mastodon. Many of the people that led me to use Twitter have not moved, and are still tweeting away. A couple have moved, but its really not a good experience searching for someone on Mastodon and coming up with nothing.
Lemmy on the other hand I'm finding to be great, because it already has small communities I can join and participate in.
still much smaller than reddit but mastodon is much worse
TL;DR: the author is more optimistic about BlueSky than about Mastodon. No reason given.
He has accounts on both but it looks like his Bluesky is inaccessible unless you have an account. In terms of "can I access your posts without logging in?", that's one point to Mastodon. Forced login has consistently been the bane of browsing Twitter for me.
Well, for one thing, Bluesky is in an invite-only pre-release state.